Antimicrobial compositions have been in use for some time and can be made of many different chemical compounds. Sodium hypochlorite is the active ingredient of many household and hospital antimicrobial products. Although disinfectants usually suffer some impairment of their activity in the presence of organic matter, the hypochlorites particularly lose much of their bactericidal potency due to the intense reactivity of both the hypochlorous acid and the hypochlorite ion with organic material generally present in the use locus. Therefore, in most instances the correct use of hypochlorite cleaning compositions requires prior removal of the organic contamination. Furthermore, chlorine containing disinfectants have an objectionable odor in use.
Saturated C.sub.2 to C.sub.6 dialdehydes such as glutaraldehyde are known to be particularly effective as bactericidal agents and do not have the disadvantages of other chemicals such as chlorine containing compounds. Dialdehydes and more particularly glutaraldehyde has been used for some time as a cold sterilant for sterilizing surgical instruments, catheters and for other uses in hospitals, doctors offices and dentists offices where heat sterilization is not convenient or practical, e.g., where instruments will not tolerate heat. Glutaraldehyde is most active as an antimicrobial agent above pH 7.
However, glutaraldehyde has several important shortcomings which has limited or hampered its use. Glutaraldehyde possesses a very lachrymatory vapor and an objectionable odor in an absorbed or liquid state. Glutaraldehyde in high concentrations, i.e., above about 50%, has a tendency to homopolymerize with consequent loss in microbicidal effectiveness. Moreover, the tendency to polymerize is accelerated at neutral to alkaline pHs where this compound possesses its greatest antimicrobial activity. If the pH of the aqueous glutaraldehyde is brought above pH 7 or if the water is allowed to evaporate, the glutaraldehyde will very rapidly polymerize and lose its antimicrobial activity. Therefore, glutaraldehyde must be stored at or below 50% concentration in water at a pH of less than 7 and preferably at a pH of less than 5.
Commercially available glutaraldehyde is available in 25 and 50 percent concentrations buffered on the acid side, i.e., pH 3.1-4.5 to minimize its homopolymerization during storage. Unfortunately at this pH, it possesses poor antimicrobial activity, and therefore the pH must be adjusted to 7.5-8.5 just before use. In order to overcome this problem several formulators have resorted to two-part systems, the first part being a use solution, typically 2-3% glutaraldehyde buffered to pH 3.1-4.5 and, the second part consisting of an activating alkalinating agent. Since the mixed solution has a limited shelf life of several weeks, the two parts are mixed just before use. This mixing activates the glutaraldehyde by increasing its pH to the optimum level. Such two-part systems are inconvenient to use and costly to the end users in regards to shipping costs in distributing use solutions. The use of an on-site activator has been unavoidable due to the instability of aqueous glutaraldehyde at pH's above 7.
Many approaches to formulating glutaraldehyde antimicrobial compositions have been disclosed in the past. For example, U.S. Pat. No. 3,968,250 by Boucher describes the formulation of a 2% liquid glutaraldehyde composition at pH 6 to 7.4 which uses sodium citrate and an alcohol or diol to stabilize the glutaraldehyde at pH 7. Glutaraldehyde absorbed on a solid inert carrier and added to a dry alkalinating agent was disclosed in Fellows, U.S. Pat. No. 4,122,192, which demonstrated germicidal and sporicidal activity of the formulations. In another approach, Warner et al., U.S. Pat. No. 4,448,977 outlines the synthesis of a mixture of liquid acetals and acid(s) that will release glutaraldehyde after water is added to the formulation, in which the conversion to glutaraldehyde requires several hours.
European Patent Application 046 375 discloses a reduced odor glutaraldehyde formulation in which a typical formulation contained 20% of a diol and 2.5% glutaraldehyde. German Patent DE 3517548 describes a disinfectant formulation that contains 18% of an anhydrous adduct of glycerin and glutaraldehyde absorbed on a mixture of surfactant, sodium tripolyphosphate, sodium sulfate and sodium cumene sulfonate. The adduct was formed after neutralizing the glutaraldehyde to pH 6.5. Although the above patents attempt to improve the stability of glutaraldehyde in various formulations, they fail to be practical and to demonstrate long term stability of the formulations.
British Patent Application No. 2,017,124 discloses the production of resinous adducts by the reaction of difunctional aldehydes, such as glutaraldehyde, with polyols such as carbohydrate sugars or certain polyhydroxy alcohols in the presence of water. However, there is no teaching or disclosure of any antimicrobial use for these compositions.
Public health officials world-wide have a general sense of apprehension concerning spilled body fluids contaminated with the AIDS virus, hepatitis or other infectious diseases. National health authorities have consistently recommended the application of a disinfectant compound to spilled body fluids which can be contaminated such as blood, vomit, urine, or feces. Such biological spills can occur in many places including schools, hospitals, nursing homes, airplanes, restaurants, daycare centers, etc.
Moisture absorbing compositions are useful in cleaning up biological spills since they absorb liquids quickly and transform them into easily handled semi-solids. Such moisture absorbing compositions are useful in hospitals and other places where biological spills such as body fluid spills occur. Antimicrobial compositions which can be placed onto a biological spill in order to absorb and disinfect the spill area before being contacted by human hands have become increasingly important. Moisture absorbing compositions containing a chlorine source as a disinfecting agent are known. However, moisture absorbing products containing an antimicrobial dialdehyde such as glutaraldehyde are not currently available.
Therefore, there is a continuing need for a stable antimicrobial composition that can be employed in a variety of ways and provide antimicrobial action on demand.